diff --git a/hdr/portab.h b/hdr/portab.h
index ae9a23b..7c965f1 100644
--- a/hdr/portab.h
+++ b/hdr/portab.h
@@ -100,6 +100,7 @@ void __int__(int);
 
 #else
 #error Unknown compiler
+We might even deal with a pre-ANSI compiler. This will certainly not compile.
 #endif
 
 #ifdef MC68K
diff --git a/kernel/init-dat.h b/kernel/init-dat.h
index 7bbde83..96727dd 100644
--- a/kernel/init-dat.h
+++ b/kernel/init-dat.h
@@ -27,6 +27,7 @@ extern __segment DosTextSeg;
 
 #else
 
-#error("unknown compiler - please adjust")
+#error unknown compiler - please adjust
+We might even deal with a pre-ANSI compiler. This will certainly not compile.
 #endif
 extern BYTE DOSFAR version_flags;       /* minor version number                 */